Retinoscope.



PATBNTED AUG. z5, 190s.l H. L. DE ZENG.

. ARElINosGoPBl APPLICATION FILED NOV. I6, 1901.

' N0 MODEL.

NITED STATESI Patented August 25,

PATENT OFFICE.

HENRY L. DE ZENG, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR OF ONE-FIFTH TO WALTER I-I. CHAMBERLIN, OF CHICAGO, ILLINOIS.

RETINOSCO PE.

SPECIFICATION forming part of Letters Patent No. 737,087, dated August 25, 1903. Application iile'd November 16, 1901. Serial No. 82,492. (No model.)

.To all whom it may concern,.-

Beitknown that LHENRY L. DE ZENG,a citizen of the United States, residing at German;l

town, Philadelphia, county of Phnadelphifa,

State of Pennsylvania, have invented a certain new and useful Improvementin Retinoscopes; and I declare the follow-ing to be a In carrying out the invention- A represents a suitable body portiomand A a suitable han-` dle, the two being engaged together in any suitable manner, the body portion being provided with the usual orifice d.' Engaged to i the body is a projecting flange B, and engaged thereto is the vmirror C, having they rection-the operator moves his own eye and usual oritice o. i

D is a suitable casing having the projection d, which is pivoted in the ears eof the collar E, the latter surrounding the handle A and rotatable thereon. Engaged in the casing D in'anydesirable manner is an electric lamp F, with binding-posts f for engaging the electric wires. I prefer to engage the lamp to a diapragm D', which engages and has an extended bearingin the end of the casing, so that the lamp can be adjusted toward and from the condensing-lens H, and the lamp may be made removable from its support, so that it can be easily replaced. In the casing is also a sleeve G, adj ustabletherein, it being provided with a projection g, ex tending through a slot CZ inthe casing,-so that the sleeve can be movedin the casing at will. In the sleeve is a condensing-lens H.

The handle A is bored longitudinally to receive the wires a', and any suitable circuitmaker-as, for instance, the sliding switch (t2-is provided, so that the operator by moving the switch across the contacts completes 'of illumination.

the circuit and lights the' lamp. A suitable `diaphragm J, having the opening j, may, if

' of retinoscopes the operator has been obliged in order tothrow the lightinto the eye underl examination to employ a suitable lamp or .ve f

other source of illumination adjacent4 either to the subjects head or his own, but independent of both and of the retinoscope. Now in the practice of retinoscopyit is well known that the usual working distance between the eyennder examination and the operator andl reiinoscope is one meter, and theoretically this distance is maintained while the operator places in the trial-frame beforethe subjects eye the necessary lenses to correct the ametropia ofthe eye under examination, this being of course determined by the fact that the reiiex from'the subjects eye either moves with the rotation of the retinoscope-mirror or against it; but in practice instead of maintaining the one-meter distance and changing thelenses until he has found the exact corthe retinoscope forward orbackward until lthe shadow reverses and then puts in the necessary lens to bring the reversal-point to the one-,meter distance. He thus quickly arrives at the desired conclusion; but in so doing he hasdestroyed the relative relation of distanceV between-the three necessary points-viz., the

dark room, with a shaded lamp for the source to secure from his testcase of lenses a lens or to nd any other object in the room, he must remove the lamp-shade, whereas with my improved instrument he has only to.di rect the light-rays of the retinoscope to any desired point. Again, where the shaded lamp is used the bundle of rays of light emit- Ico ted through the small opening in the shade (usually from a quarter of an inch to one inch in diameter) is so sinall that it is very dithcult to bring the retinoscope to the proper position with relation to the light and subjects eye to correctly direct the rays. The same ditticulty arises when an uncovered source of light is used. Again, by bringing the light up to and causing it to be carried by the retinoscope a great saving in the candle-power of the light is accomplished. This reduction of candle-power has also the advantage of reducing the size of the point from which the light emanates, and consequently is more easily and eiectively condensed and controlled. Again, owing to the compactness and portability of my device it can be easily carried into a hospital-room or other point away from the operators room and used upon the subjects eye when the person is in other than an upright position.

Instead of making the mirror() stationary it might be adjustable, as shown in Fig. 2, it

being mounted in a ring C by the pivots c' and the ring being mounted on the frame by the pivots c2, so that the mirror is adjustable in any direction. Instead of the casing D being adjustably mounted on the handle A it might be stationary thereon. So, also, instead of an orifice c in the mirror the latter might be imperforate, and a portion corresponding to the opening c might be made transparent, and by the term opening7 I mean any means for enabling the light to pass through. The mirror may be either flat or curved.

What I claim isl. In a portable retinoscope, the combination with the supporting means of a source of illumination carried thereby, a mirror also carried thereby adapted to refiect the light from the source of illumination, said mirror provided with means permitting the light to pass therethrough and a condenser between the source ot' illumination and the mirror.

In a portable retinoscope, the combination with the mirror thereof, of a casing connected to said mirror and a source of illumination in said casing the light from which is reflected by said mirror, both said mirror and casing carried by a handle that moves both simultaneously.

8. In a portable retinoscope, the combination of a body portion having a suitable handle, a mirror mounted thereon and carried thereby, means for permitting the light to pass through said mirror and body portion, a casing carried by the body portion said casing carrying an electric lamp the rays from which are directed against the mirror, and a condenser located between electric lamp and mirror.

4. In a portable retinoscope, the combination of a body portion havinga suitable handle, a mirror mounted thereon and carried thereby, means for permitting the light to pass through said mirror and body portion, a casing carried by the body portion said casing carrying an electric lamp the rays from which are directed against the mirror, a condenser located between electric lamp and mirror, and adiaphragm provided with means for permitting the light to pass through and located between light and mirror.

5. In a portable retinoscope, the combination of a body portion having a suitable handle, a mirror mounted thereon and carried thereby, means for permitting the light to pass through said mirrorand body portion, a casing carried by the body portion said casing carrying an electric lamp the rays from which are directed against the mirror, an adjustable condenser located between electric lamp and mirror, and a diaphragm located between the condensing-lens and mirror.

In testimony whereof I sign this specication in the presence of two witnesses.

HENRY L. DE ZENG.

Witnesses:

GRACE B. I-IURLBUT, PERCY E. DROUGHMAN. 

